Heparin-Induced Thrombocytopenia Antibody Testing and Its Cost Effectiveness: Taking a Financial HIT

Introduction Heparin induced Thrombocytopenia (HIT) is a life threatening condition that can lead to significant morbidity and mortality in hospitalized patients. Thrombocytopenia in the setting of unfractionated heparin (UFH) exposure is a common occurrence in hospitalized patients and its diagnosis and management is associated with increased costs to the healthcare system. There is a 5-10X decreased risk of HIT with low molecular weight heparin (LMWH)(Martel N, et al. Blood. 2005;106 (8):2710-2715) while the incidence with fondaparinux is much more rare (Warkentin TE et al; Blood 2005, 106: 3791-3796). We conducted a single center, retrospective study to assess the correlation of HIT antibody (Ab) testing to '4T' score and the associated financial burden in our institution. Method Data collection Using retrospective chart review, we identified 78 hospitalized patients between 11/11/15 and 6/7/16 from various departments that underwent HIT Ab testing. The '4T' score was calculated as per Table 1. Data including admission service, type and duration of anticoagulation (AC) prior to and after HIT testing, HIT Ab and Serotonin release assay (SRA) positivity, type and duration of non-heparin AC and days of hospitalization were collected. HIT Ab was measured using platelet factor 4 complexed polyvinyl sulfonate (PVS) coated to the wells of a microtiter plate (Labcorp Burlington Test 150075). Patients with positive HIT (Optic Density>0.4) were reflexed to confirmatory SRA (LabCorp Burlington Test 150018). Cost Analysis Pharmacy acquisition cost of non-heparin AC (argatroban /fondaparinux) used as empiric treatment during the HIT testing period was recorded. Pharmacy acquisition cost was also used to predict cost of prophylactic LMWH and fondaparinux for the same duration. Daily dose of continuous UFH was standardized to a 70Kg patient/day. The cost of testing for HIT incurred by the facility was obtained. Statistical analysis was done using ANOVA on VassarStats.net online computation. Results Seventy eight patients had HIT Ab evaluated (Table 2). 26.9% (n=21) had a positive HIT Ab test, and 2.5% had a positive SRA test (n=2). Of the 78 cases analyzed, 48 were categorized as low risk, 24 as intermediate, and 8 as high using the 4T score. HIT Ab testing was positive in 23.9% of low risk, 29% of intermediate risk and 37.5% of high risk patients. SRA was positive in only 2.5% of cases; 1 in the low risk and 1 in the high risk group (n=2) (Table 2). Breakdown of AC during hospital stay showed that 52% (n=41) had UFH on admission, 70% (n=29) of which was for DVT prophylaxis; however 56% (n=23) of these did not have heparin exposure within 100 days of admission. 18% (n=14) were placed on SCDs, 6 of which had no known heparin exposure within 100 days of admission. 23% (n=18) were exposed to prophylactic LMWH, 2.5% (n=2) to therapeutic LMWH, 1.2% (n=1) to dabigatran, apixaban and fondaparinux each (Table 3). Cost Analysis The total average cost per patient with suspected HIT requiring laboratory evaluation was $431.15 (n=78). If a patient required full dose non-heparin anticoagulation, the average cost increased to $1274.98 per patient (n=20) and average duration of anticoagulation was 4 days. Average length of hospitalization for patients suspected of HIT was 18.7 days. Using enoxaparin as an anticoagulation during this period would have cost on average $68.46 per patient, while the use of fondaparinux would cost $179.01. Conclusion Evaluation for HIT and empiric management poses a significant burden of expense on our strained healthcare system. The 4T score has been useful in predicting HIT positivity in other studies (Lo GK, J Thromb Haemost. 2006 Apr;4(4):759-65). In this study conducted in a real-world clinical setting however, we found the 4T score was not universally applied to calculate pretest probability. A suspicion of HIT cost on average $431 per patient per hospitalization. A positive HIT Ab lead to an expense of $955. Confirmed HIT by SRA, resulted in an expense of $1557 per patient per hospitalization. Of note, length of stay and patient discomfort was not included in the analysis. Improved education regarding pretest probability using 4T score is warranted, however using LMWH or non-heparin alternative as DVT prophylaxis may be the most cost-effective approach in today's cost-conscious, high-value healthcare system. Disclosures No relevant conflicts of interest to declare.

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Testing for Heparin Induced Thrombocytopenia: Comparison of Practice at an Academic Center with Choosing Wisely Guidelines

Blood ◽

10.1182/blood.v126.23.3469.3469 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3469-3469

Author(s):

DiMaria C Erica ◽

Alex Trussler ◽

Dyba Janique ◽

David Lee ◽

Michael J. Rauh ◽

...

Keyword(s):

Research Funding ◽

Clinical Characteristics ◽

Low Risk ◽

Choosing Wisely ◽

Observer Variability ◽

Heparin Induced Thrombocytopenia ◽

Inter Observer Variability ◽

Test Probability ◽

4T Score ◽

Heparin Exposure

Abstract Background: The American Society of Hematology Choosing Wisely Guidelines 2014 recommend against testing for treatment of Heparin Induced Thrombocytopenia (HIT) in individuals at low risk, defined by a 4T score ≤ 3. Diagnosis of HIT relies on a combination of clinical characteristics and laboratory testing. The 4T score is a pretest probability score that defines clinical characteristics of HIT with reported negative predictive value of 99.8%. A new scoring model, the HIT Expert Probability (HEP) score, was introduced in 2010 and postulated to reduce inter-observer variability. The primary objective of this study was to examine compliance with guidelines at our institution; a 456 bed university hospital. Secondary objectives were to compare the performance of the 4T and HEP score in regards to inter-observer variability and the predictive value of low risk scores. Methods: Local practice is initial testing with anti-PF4 antibody enzyme immunoassay (EIA), and subsequent reflex serotonin release assay (SRA) if the EIA is positive or indeterminate. Consecutive patients with requests for HIT testing were identified from laboratory records. With Research Ethics Board approval, retrospective chart review was conducted by 3 reviewers who independently applied 4T and HEP scores; discrepancies were resolved by consensus. Adverse events including thrombosis, skin necrosis, heparin infusion reactions, bleeding (classified as major by ISTH criteria) and mortality were recorded. Inter-observer variability was assessed using the intraclass correlation (ICC). Results: Between 2013 January 1 and 2015 Feb 21, 76 patients were referred for EIA testing. Excluded from this analysis were 7 patients with prior history of HIT or with testing requested from an outside institution. Of the remaining 69, median age was 67 years (range 24-90), 36 (56%) were male, 49 (71%) admitted with a medical diagnosis and 20 (29%) under a surgical service. Hematology service was consulted at some point during admission in 25 (36%). Pretest probability was documented in 16 (23%). A greater percentage of patients with documented pre-test probability had a hematology consult 11 (69%) than patients without 5 (31%). Also, 36 (86%) patients without a documented pre-test probability were considered low risk by the 4T score. Table 1.Scoring systemPre-test probabilityTotalN=69 (%)EIA positiveSRA positive*4TLow (≤3)42 (61)9 (13)1* (1)Intermediate (4-5)25 (36)10 (14)4 (6)High (6-8)2 (3)2 (3)1 (1)HEPLow (≤2)35 (51)7 (10)1* (1)Intermediate (2-5)20 (29)17 (25)1 (1)High (≥6)14 (20)7 (10)4 (6)*If SRA inconclusive, result confirmed with anti-PF4 IgG**Admitted with ischemic leg requiring catheter directed thrombolysis. Rapid onset thrombocytopenia within 24 hours of heparin exposure. Prior heparin exposure 150 days prior. Heparin stopped. No alternative anti-coagulation. No sequelae of HIT. The ICC for the pre-test probabilityscores was0.796(95% CI 0.714- 0.860) for 4T and 0.742 (95% CI- 0.645-0.821) for HEP score. By risk category, ICC for 4T score was 0.667 (95% CI 0.553 - 0.765) and HEP score was 0.702 (95% CI 0.553 - 0.765). HIT testing was performed in patients classified as low risk; 42 (61%) according to 4T and 35 (45%) according to HEP score. Among the 42 classified as low risk by 4T score, heparin was held in 26 (55) % pending results of testing and alternative anticoagulation commenced in 14 (33%) (fondaparinux 13, argatroban 1), at prophylactic dose in 12 and at therapeutic dose in 1 without a separate indication for anticoagulation. One low risk patient suffered major bleeding and 2 had thrombotic events. Overall, bleeding occurred in 10 (14%), major in 6 (9%), and thrombotic events occurred in 9 (13%). One patient presenting with septic shock, who developed thrombocytopenia with 4T score of 4, received argatroban and died on the same day from intracranial hemorrhage. All cause mortality during admission was 23 (33%). Conclusion: Compliance with Choosing Wisely Guidelines at our institution is low, and potentially associated with unnecessary financial expenditure and patient harm due to over-testing and over-treatment. We did not observe benefit of the more complex HEP score over the 4T score. Efforts are underway to increase awareness and align practice with recommendations. Disclosures James: Biogen Idec: Honoraria; Bayer: Honoraria, Research Funding; Octapharma: Honoraria, Research Funding; Baxter: Honoraria; CSL Behring: Honoraria, Research Funding.

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A Rapid Heparin Antibody Detection Assay Performs Better Than 4T's Score in Predicting HIT Diagnosis: A Single Community Medical Center Retrospective Analysis

Blood ◽

10.1182/blood.v124.21.1457.1457 ◽

2014 ◽

Vol 124 (21) ◽

pp. 1457-1457 ◽

Cited By ~ 1

Author(s):

Srikant Nannapaneni ◽

Ishan Malhotra ◽

Michael Simon ◽

Phone Oo ◽

Trishala Meghal ◽

...

Keyword(s):

High Risk ◽

Roc Curve ◽

Predictive Value ◽

Risk Groups ◽

Low Risk ◽

Receiver Operating Characteristics ◽

Operating Characteristics ◽

Test Result ◽

4T Score ◽

Receiver Operating

Abstract Introduction: The diagnosis of heparin induced thrombocytopenia (HIT) and thrombosis (HITT) is challenging due to poor availability of the gold standard serotonin releasing assay (SRA) and suboptimal positive predictive value from clinical scoring models such as 4T score. A common algorithm used for diagnosing HIT is: 4T's pretest probability score estimation in cases suspected of HIT; followed by HIT antibody test in the intermediate to high risk groups; followed by confirmation with SRA test in HIT antibody positive patients. Since 2011, a Particle Immune-Filtration Assay (PIFA) Heparin/Platelet Factor 4 Rapid Assay (HPF4-RA) (Akers Bioscience, Inc, Thorofare, NJ) became available in our medical center and test results were available on the same day. We observed that HPF4-RA test was being routinely ordered along with SRA test at the same time. We performed this retrospective analysis to evaluate and compare the predictive performance for SRA positive HIT diagnosis using 4T score or HPF4-RA. We applied a regression analysis model, to calculate area under receiver operating characteristics (ROC) curve. Methods: A list of all consecutive patients who had HIT antibody test and/or SRA test performed between January 2010 and June 2013 was obtained, which consisted of 402 patients. Patients with duplication of tests were deleted from analysis. 283 patients had results reported for both HPF4-RA (positive in n=42, negative in n=241) and SRA tests (positive in n=16 and negative in n=267); and these results were used for calculation of HPF4-RA prediction model. Two patients had HPF4-RA negative result but SRA positive test result. 4T's scores were calculated for 125 patients, consisting of all HPF4-RA positive patients (n=42), and patients randomly selected from the total HPF4-RA negative pool (n=83). Electronic medical records were reviewed for temporal trend of platelet counts, diagnosis, medication use, Doppler tests and competing causes of thrombocytopenia. Persons calculating the 4T's score were blinded to the laboratory test results. Results: Stratification of the patients with 4T's score analysis (n=125) revealed that the distribution of SRA positive patients (n=16) was 31.3% (n=5) in low risk, 31.3% (n=5) in intermediate risk, and 37.5% (n=6) in high risk groups; while the distribution of SRA negative patients (n=109) was 45.9% (n=50) in low risk, 43.1% (n=47) in intermediate risk and 11.0% (n=12) in high risk groups. The area under receiver operating characteristics (ROC) curve for 4T score as a continuous variable to predict SRA positive HIT was 0.659 (95% CI 0.516 - 0.802; p = 0.041), and the area under ROC curve for HPF4-RA to predict SRA positive HIT was 0.818 ( 95% CI 0.712 - 0.924; p = 0.00) (Figure 1). HPF4-RA test also showed better overall prediction parameters for HIT as shown in Table 1. A combination of HIT HPF4-RA positive result and a 4T score ≥ 4 did not increase the area under ROC curve for prediction of SRA positive HIT. Abstract 1457. Table1: Predictive performance of 4T's score and HPF4-RA for HIT (defined by positive SRA) Sensitivity (95% CI) Specificity (95% CI) PPV (95% CI) NPV (95% CI) Number of patients (%) 4T's score ≤ 3 (Low Risk) 0.31 (0.11 – 0.59) 0.72 (0.64 - 0.79) 0.11 (0.03 - 0.23) 0.91 (0.84 - 0.95) 56 (44.8) 4T's score ≥ 4 (Intermediate and High Risk) 0.69 (0.41-0.89) 0.39 (0.29 - 0.48) 0.14 (0.72 - 0.24) 0.89 (0.77 - 0.96) 69 (55.2) 4T's score ≥ 6 (High Risk) 0.37 (0.15-0.65) 0.82 (0.74 - 0.89) 0.24 (0.09 - 0.45) 0.90 (0.82 - 0.95) 17 (13.6) HPF4-RA Test 0.88 (0.62-0.98) 0.86 (0.81- 0.90) 0.26 (0.16 - 0.41) 0.99 (0.96 - 0.99) 283 PPV: Positive Predictive Value. NPV: Negative Predictive Value Figure 1: Receiver Operating Characteristics (ROC) curve of the 4T's score and HPF4-RA test result for determining the presence of HIT (defined by positive SRA). Figure 1:. Receiver Operating Characteristics (ROC) curve of the 4T's score and HPF4-RA test result for determining the presence of HIT (defined by positive SRA). Conclusions: Both 4T's score and HPF4-RA testing predict SRA positive HIT more than chance; however HPF4-RA testing predicts SRA positive HIT better than 4T's scores with higher sensitivity, specificity and NPV. This result challenges the pretesting algorithm for selecting patients for confirmatory SRA testing to diagnose HIT. Instead of using 4T's score as a screening tool for selecting patients for HPF4 antibody testing; rapid HPF4 antibody assays when available, should be considered as upfront screening tool and positive results considered for confirmatory SRA testing for diagnosis of HIT. Further studies are warranted to confirm this data. Disclosures No relevant conflicts of interest to declare.

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Testing for Heparin Induced Thrombocytopenia in Hospitalized Patients: In Line with Evidence?

Blood ◽

10.1182/blood-2021-153637 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 1957-1957

Author(s):

Udhayvir Singh Grewal ◽

Shiva Jashwanth Gaddam ◽

Sahith Reddy Thotamgari ◽

Tyiesha Brown ◽

Kavitha Beedupalli ◽

...

Keyword(s):

Conflicts Of Interest ◽

Heparin Therapy ◽

Hospitalized Patients ◽

Antibody Testing ◽

Drug Induced ◽

Platelet Factor ◽

Heparin Induced Thrombocytopenia ◽

Clinical Probability ◽

Test Probability ◽

4T Score

Abstract Background: Heparin-induced thrombocytopenia (HIT) is an immune complication of heparin therapy caused by antibodies to complexes of platelet factor 4 (PF4) and heparin. Both clinical probability and laboratory testing are needed for establishing a diagnosis of HIT. The 4Ts clinical scoring system, due to a very high negative predictive value when low, offers a robust means to exclude a diagnosis of HIT. However, these strategies are under-employed in clinical practice and limited evidence indicates a high prevalence of over-testing for HIT. Methods: This retrospective analysis was conducted to identify patients who underwent heparin/PF4 antibody testing over a period of 12 months. The testing was performed using an ELISA-based IgG anti-heparin/PF4 antibody assay and an optical density (OD) of 0.4 was used as a cut-off for a positive value. Electronic medical records were reviewed for 4T score documentation, anti-PF4 results, SRA testing and 4T scores were retrospectively calculated for all the patients. SAS v9.4 (Cary, NC) was used for statistical analysis. Results: A total of 105 patients who underwent anti-PF4 antibody testing were included for analysis. Majority of the patients in our cohort were admitted in an intensive care unit setting (75/105,71.4%). On chart review, only 17 patients (16.2%) were noted to have documentation of 4T score. Based on the retrospectively calculated 4T scores, 60 patients (57.1%) had low pre-test probability, 41 (39%) had intermediate pre-test probability and 4 (3.8%) patients were noted to have high pre-test probability. Anti-PF4/heparin antibodies were positive in 9 patients, of which 5 (55.5%) patients did not undergo concomitant SRA testing. Out of 9, 4 (44.4%) had weakly positive (0.4-1.0 OD units), 2 (21.1%) had strongly positive (1.0-2.0 OD units) and 2 (21.1%) patients had very strongly positive (>2 OD units) anti-PF4 antibody titers. Out of 105 patients, SRA was tested in 11 patients (10.5%) and was noted to be positive in 1 (0.95%). Overall, 2 patients were diagnosed and treated for HIT, out of which the diagnosis was not confirmed with SRA in 1 patient (due to high pre-test probability and very strong anti-PF4 titers). In the remaining patients, sepsis (48, 46.6%) and drug-induced thrombocytopenia (29, 28.2%) emerged as the most common possible causes of thrombocytopenia. Conclusion: Among hospitalized patients, over-testing for HIT is common. Practices to promote 4T score documentation and evidence-based anti-PF4 testing may help prevent unnecessary costs associated with serological testing and costly alternate anticoagulants. To improve overall outcomes, clinicians should also attempt to identify and treat other more likely causes of thrombocytopenia, especially in patients with low pre-test probability for HIT. Disclosures No relevant conflicts of interest to declare.

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Utility of Optical Density Values from Heparin-Platelet Factor 4 Antibody Testing and Probability Scoring Models To Diagnose Patients with Heparin Induced Thrombocytopenia.

Blood ◽

10.1182/blood.v108.11.1475.1475 ◽

2006 ◽

Vol 108 (11) ◽

pp. 1475-1475

Author(s):

Kim A. Janatpour ◽

Robert C. Gosselin ◽

William E. Dager ◽

Andrew Lee ◽

John T. Owings ◽

...

Keyword(s):

High Risk ◽

Optical Density ◽

Predictive Value ◽

Platelet Factor 4 ◽

Platelet Factor ◽

Predictive Values ◽

Heparin Induced Thrombocytopenia ◽

Sensitivity Specificity ◽

Test Probability ◽

4T Score

Abstract Background: Heparin induced thrombocytopenia (HIT) is a potentially life threatening complication of heparin administration caused by antibodies directed to the heparin-platelet factor 4 (PF4) complex and characterized by thrombocytopenia with a seemingly paradoxical high risk of thrombosis. Diagnosis is challenging, and is based on both clinical suspicion and laboratory detection of heparin-PF4 antibodies. The Warkentin 4 T’s “pre-test” probability and Chong’s “post-test” probability models have been developed to aid the diagnosis of HIT. Enzyme-linked immunoabosorbant assay (ELISA) laboratory measurement of heparin-PF4 antibodies is commonly used but has a low positive predictive value for thrombosis. Recent reports suggest that using an ELISA optical density (OD) value of ≥ 1 may improve the predictive value for thrombosis. Methods: We performed a retrospective analysis of 105 patients with suspected HIT who were treated with a direct thrombin inhibitor and evaluated the anti-heparin-PF4 ELISA OD values and Warkentin 4 T’s scores for sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) using the Chong’s score to define HITBoth the manufacturer’s OD threshold of 0.4 and ≥ 1 were evaluated. Table 1. Comparison of sensitivity, specificity, and predictive values for 4 T’s and OD levels, alone and in combination Sensitivity (%) Specificity (%) NPV (%) PPV (%) For calculations, Chong’s categories of definite/probable and unlikely were used to define presence or absence of HIT. 4T’s score (high and low) 81 100 80 100 OD level 0.4 69 75 65 78 OD level ≥1 38 85 52 77 4T’s + OD 0.4 94 100 94 100 4T’s +OD ≥1 69 85 81 75 Results: The sensitivity, specificity and predictive value of ELISA alone were inferior to the 4 T’s clinical scorings system. The sensitivity and negative predictive values of the 4T’s score were improved by considering positive or negative ELISA test results. Conclusions: Consistent with previous reports, the PPV of a high probability 4T score alone was 100%. Thus, ELISA results might not change clinical decisions in this situation. Alternative anticoagulation might be inappropriately withheld in 20% of patients if a low probability 4T score alone were to be used for decision-making. The addition of ELISA data using an OD level of 0.4 increased the NPV to a threshold that might be considered clinically acceptable (94%) to withhold therapy. Addition of an OD level of ≥ 1 did not improve the PV of the 4 T’s. However, in contrast to other studies that found better predictive value to using this higher OD threshold, our study group was limited to people considered high risk for HIT. Validation of this strategy in a prospective trial with clinical endpoints should be considered.

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Enforcing the 4T: Including a Hard Stop 4T Calculator into the Electronic Medical Record for Heparin Induced Thrombocytopenia

Blood ◽

10.1182/blood-2018-99-110375 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2442-2442

Author(s):

Thomas A Ollila ◽

Adam Zayac ◽

Adam J Olszewski ◽

Ross W Hilliard ◽

David Riley ◽

...

Keyword(s):

Quality Of Care ◽

Positive Predictive Value ◽

Predictive Value ◽

Clinical Management ◽

Research Funding ◽

Heparin Induced Thrombocytopenia ◽

Alternative Anticoagulation ◽

4T Score ◽

Heparin Exposure

Abstract Background: Among many causes of thrombocytopenia acquired during hospitalization, heparin-induced thrombocytopenia (HIT), an immune complex-mediated thrombogenic state with high morbidity and mortality, is one of the most feared etiologies. The clinical '4T' score is an established method to assess risk for HIT and guide immediate management(Lo, Juhl et al. 2006). However, the 4T score is not consistently used by clinicians, leading to potential over-testing and suboptimal management of suspected HIT. Our objective in this Quality Improvement (QI) project was to implement a mandatory 4T calculator (4TC) into the electronic medical record (EMR) to improve the positive predictive value of HIT antibody (HITA) testing, decrease the incidence of testing of low-risk patients, and to improve clinical management of suspected HIT. Methods: We developed a 4TC that assisted clinicians by integrating EMR-derived data on heparin exposure and the five most recent platelet counts with a link to an online calculator as well as clinical suggestions (Figure). As a part of this QI project, clinicians were required to enter the calculated 4T score before ordering a polyspecific HITA assay, which serves as the screening test for HIT in our institution. We reviewed laboratory records for all HITA tests performed over a six-month period, including 3 months before and after the implementation of a "hard stop" for HITA order in the EMR. We extracted data on the ordering hospital service team, 4T score documented in notes (if any), as well as quality of care indicators including rates of clinically recommended heparin cessation and initiation of alternative anticoagulation in the subgroup of patients with intermediate or high 4T score at the time of HITA order. In this QI project, we refrained from any statistical testing and summarized pre-specified outcome measures: incidence of HITA testing, positive predictive value of the HITA assay, and quality of care indicators. Results: We identified 99 (53 prior to the 4TC and 46 post) cases of HITA orders in the study period, among which there were 4 cases of confirmed HIT (either with positive IgG or positive serotonin-release assay [SRA]). Three HIT cases occurred after the 4TC was implemented. After the implementation of the 4TC, the positive predictive value for the HITA assay increased from 9% to 21%. The rate of clinically appropriate heparin order discontinuation increased from 72% to 88%, as did the initiation of alternative anticoagulation from 14% to 27%. HITA assay was most commonly ordered by the internal medicine service (35% of tests), non-cardiac intensive care service (30%), coronary care and cardiothoracic surgery services (21%), neurology (5%), and general surgery/other services (9%). Implementation of the 4TC did not significantly change this distribution, but the overall incidence of HITA orders decreased from 4.0 to 3.4 per 1000 admissions. We observed a high frequency of confirmatory SRA testing requested (18%), which is the reflex confirmatory test performed at our institution, even in cases of negative polyspecific HITA or HIT IgG. Conclusions: Addition of a 4T score calculator into the EMR which provides immediate feedback on patient's prior heparin exposure and recent platelet counts allows clinicians to consistently use the 4T score when considering HIT. Importantly, it also helps to educate non-hematologists on the proper management of HIT. Improved predictive value of the HITA assay suggests that our 4TC led to ordering HITA in a more appropriate patient population. We also demonstrated improved quality of care for suspected HIT, with increased rates of heparin cessation and initiation of alternative anticoagulation in patients with intermediate or high pre-test probability. Identifying clinical teams that order a disproportionate number of HITA assays will help us to direct education to improve clinical management. This QI project has led to other areas of improvement, particularly with regard to rational ordering of the SRA. At only three months of review since implementation of the 4TC, we have noted an improvement in the management of suspected HIT and a slight reduction in the incidence of testing. With continued review, we hope to demonstrate further improvement, as practitioners continue to use the 4TC and rely on clinical rationale rather than reflexive laboratory testing when evaluating thrombocytopenia in the hospital. Disclosures Olszewski: TG Therapeutics: Research Funding; Spectrum Pharmaceuticals: Consultancy, Research Funding; Genentech: Research Funding. Reagan:Alexion: Honoraria; Takeda Oncology: Research Funding; Pfizer: Research Funding.

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"Has the Pendulum Swung Too Far? Evaluation of the Appropriate Use of VTE Prophylaxis for Medical Inpatients."

Blood ◽

10.1182/blood.v128.22.4745.4745 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4745-4745

Author(s):

Courtney A Fay ◽

Marijeta Pekez ◽

Anna Thomas ◽

Bhakti Deshmukh ◽

Naveed Jan ◽

...

Keyword(s):

Risk Assessment ◽

High Risk ◽

Hospitalized Patients ◽

Low Risk ◽

Prediction Score ◽

Admission Criteria ◽

Vte Prophylaxis ◽

Medical Inpatients ◽

Current Guidelines ◽

Anticoagulated Patients

Abstract Introduction: Venous thromboembolism (VTE) is the most common cause of hospital death. Pharmacologic intervention has become the standard of care in the prevention of VTE in hospitalized patients. However, studies have not been able to show a consistent benefit of VTE prophylaxis on mortality in hospitalized medical patients. Medical inpatients are a very heterogenous group; not all of them need VTE prophylaxis. Current guidelines recommend the use of heparin or related drugs as VTE prophylaxis in medical inpatients at increased risk of thrombosis, and recommends against pharmacologic VTE prophylaxis in patients at low risk. Several risk assessment modules including the Padua Prediction Score, attempt to identify patients at high-risk for thromboembolism. The goal of the study was to evaluate if risk is assessed and defined by clinicians prior to prescribing VTE prophylaxis. Methods A retrospective chart analysis was performed for patients admitted to the medicine service from January 2015 to June 2015. The initial arrival orders as well as the history and physical documented by the admitting physician were reviewed to determine if the risk of VTE was recorded and if VTE prophylaxis was prescribed. Patients were stratified as either admission or observation and the type of anticoagulation was recorded. If the admitting physician did not perform a VTE risk assessment, risk of VTE was calculated using the Padua Prediction Score. Results: Data was collected on a total of 648 patients. 314 (48%) patients met admission criteria and 334 (52%) patients met observation criteria. Chemical VTE prophylaxis was prescribed for 262 of the 314 (83%) admissions and 215 of the 334 (64%) observation patients. Of the 262 admissions that received chemical VTE prophylaxis, 240 (92%) of these patients were considered low-risk based on the Padua Prediction Score (Figure 1). 201 of the 215 (93%) observation patients that received chemical VTE prophylaxis were calculated to be low-risk (Figure 2). Adverse events were found to occur in 7 of the 648 (1.1%) patients that received chemical VTE prophylaxis. Conclusion: Inappropriate use of chemical VTE prophylaxis was observed in a majority of medical inpatients. Discussion: Routine use of VTE prophylaxis is not recommended. Current guidelines advise practitioners to evaluate all hospitalized patients for risk of VTE and bleeding prior to the initiation of VTE prophylaxis. Risk assessment tools such as the Padua Prediction Score help discriminate those patients at high risk of VTE and bleeding. However, this study shows that most clinicians do not perform a proper risk assessment for thromboembolism and bleeding prior to the initiation of VTE prophylaxis. Significant bleeding and thrombocytopenia were the most common complications identified in patients who received pharmacologic intervention. Although the rate of complications was low, further studies are needed to address additional negative consequences from the overuse of anticoagulation such as cost, nursing time and patient discomfort. Figure 1 VTE risk assessment of anticoagulated patients who met admission criteria Figure 1. VTE risk assessment of anticoagulated patients who met admission criteria Figure 2 VTE risk assessment of anticoagulated patients who met observation criteria Figure 2. VTE risk assessment of anticoagulated patients who met observation criteria Disclosures No relevant conflicts of interest to declare.

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Identifying patients at high risk of heparin-induced thrombocytopenia-associated thrombosis with a platelet activation assay using flow cytometry

Thrombosis and Haemostasis ◽

10.1160/th16-06-0482 ◽

2017 ◽

Vol 117 (01) ◽

pp. 127-138 ◽

Cited By ~ 7

Author(s):

Takuma Maeda ◽

Katsura Nakagawa ◽

Kuniko Murata ◽

Yoshiaki Kanaumi ◽

Shu Seguchi ◽

...

Keyword(s):

High Risk ◽

Platelet Activation ◽

Heparin Induced Thrombocytopenia ◽

Activated Platelets ◽

Activation Assay ◽

Significant Difference ◽

Increased Sensitivity ◽

Supplementary Material ◽

Clinical Profiles ◽

Heparin Exposure

SummaryTo diagnose heparin-induced thrombocytopenia (HIT), detection of platelet-activating antibodies (HIT antibodies) is crucial. However, serum platelet activation profiles vary across patients and depend on test conditions. We evaluated the association between clinical outcomes and platelet-activating profiles assessed by a platelet microparticle assay (PMA), which detects activation of washed platelets induced by HIT antibodies, in 401 consecutive patients clinically suspected of having HIT. We made modifications to the assay, such as donor selection for washed platelets that increased sensitivity. Serum that activated platelets at a therapeutic (but not high) heparin concentration was defined as positive. Of these, serum that activated platelets within 30 minutes or in the absence of heparin was defined as strongly positive. The remaining samples were considered weakly positive. As a result, 97 % and 93 % of patients who tested strongly and weakly positive had clinical profiles consistent with HIT, respectively. The incidence of thromboembolic events (TEEs) after heparin exposure in patients who tested strongly positive, weakly positive, and negative was 61 %, 40 %, and 29 %, respectively. Among patients who did not experience a TEE on the day HIT was suspected, there was no significant difference in the cumulative incidence of subsequent TEEs between patients who tested strongly and weakly positive when argatroban was initiated on the same day (19.0 % vs 7.1 %, p=0.313), but there was a significant difference when argatroban therapy was delayed by one or more days (61.1 % vs 17.6 %, p=0.007). The modified PMA is effective in diagnosing HIT and identifying patients at high risk for HIT-associated TEEs.Supplementary Material to this article is available online at www.thrombosis-online.com.

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Papillary Thyroid Carcinoma: How Radical Lymphadenectomy Should be Performed?

Swiss Surgery ◽

10.1024/1023-9332.9.2.63 ◽

2003 ◽

Vol 9 (2) ◽

pp. 63-68

Author(s):

Schweizer ◽

Seifert ◽

Gemsenjäger

Keyword(s):

High Risk ◽

Papillary Thyroid Carcinoma ◽

Thyroid Carcinoma ◽

Low Risk ◽

Papillary Thyroid ◽

Sentinel Nodes ◽

Fand Sich ◽

Radical Lymphadenectomy ◽

N Status

Fragestellung: Die Bedeutung von Lymphknotenbefall bei papillärem Schilddrüsenkarzinom und die optimale Lymphknotenchirurgie werden kontrovers beurteilt. Methodik: Retrospektive Langzeitstudie eines Operateurs (n = 159), prospektive Dokumentation, Nachkontrolle 1-27 (x = 8) Jahre, Untersuchung mit Bezug auf Lymphknotenbefall. Resultate: Staging. Bei 42 Patienten wurde wegen makroskopischem Lymphknotenbefall (cN1) eine therapeutische Lymphadenektomie durchgeführt, mit pN1 Status bei 41 (98%) Patienten. Unter 117 Patienten ohne Anhalt für Lymphknotenbefall (cN0) fand sich okkulter Befall bei 5/29 (17%) Patienten mit elektiver (prophylaktischer) Lymphadenektomie, und bei 2/88 (2.3%) Patienten ohne Lymphadenektomie (metachroner Befall) (p < 0.005). Lymphknotenrezidive traten (1-5 Jahre nach kurativer Primärtherapie) bei 5/42 (12%) pN1 und bei 3/114 (2.6%) cN0, pN0 Tumoren auf (p = 0009). Das 20-Jahres-Überleben war bei TNM I + II (low risk) Patienten 100%, d.h. unabhängig vom N Status; pN1 vs. pN0, cN0 beeinflusste das Überleben ungünstig bei high risk (>= 45-jährige) Patienten (50% vs. 86%; p = 0.03). Diskussion: Der makroskopische intraoperative Lymphknotenbefund (cN) hat Bedeutung: - Befall ist meistens richtig positiv (pN1) und erfordert eine ausreichend radikale, d.h. systematische, kompartiment-orientierte Lymphadenektomie (Mikrodissektion) zur Verhütung von - kurablem oder gefährlichem - Rezidiv. - Okkulter Befall bei unauffälligen Lymphknoten führt selten zum klinischen Rezidiv und beeinflusst das Überleben nicht. Wir empfehlen eine weniger radikale (sampling), nur zentrale prophylaktische Lymphadenektomie, ohne Risiko von chirurgischer Morbidität. Ein empfindlicherer Nachweis von okkultem Befund (Immunhistochemie, Schnellschnitt von sampling Gewebe oder sentinel nodes) erscheint nicht rational. Bei pN0, cN0 Befund kommen Verzicht auf 131I Prophylaxe und eine weniger intensive Nachsorge in Frage.

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